This research will investigate the link between motivation and early language learning in Down Syndrome toddlers with delayed expressive language. In particular, the study will examine the role of control of speech output in increasing motivation towards language learning as a whole, including both comprehension and production. Specifically, our aims are to identify measurable motivation behaviors associated with language mastery tasks in Down Syndrome toddlers, to determine the extent to which control over speech output results in increased motivation behaviors during language tasks in this population, and to identify what impact control of speech output has on language learning and use, compared to other interventions. In the proposed research, three experimental conditions are set up. In the first condition, the language delayed toddlers are allowed control over speech output on a computer-based language acquisition system. In the second condition, the toddlers are allowed control over a graphics display on the computer. The third condition, as a control, introduces sign language plus picture boards in sessions where the computer is absent. Motivation behaviors and language learning and use are measured under each of these three conditions. This project will be carried out by a linguist with a background in normal language acquisition and child language disorders and by a developmental psychologist. Otologic and audiologic evaluation prior to each condition will allow us to test for effects of otitis media and mild hearing loss on language and motivation behaviors. Preliminary studies showed that providing a population of Down Syndrome and other developmentally disabled language delayed toddlers at the beginning stages of language acquisition with a speech output device greatly increased their motivation towards language learning and use and helped them enter the language mainstream at a developmentally appropriate age. Early language intervention is crucial because language is the most critical cognitive skill being developed by the child for eighteen months to three years of age. The results of this study will provide a research base for an innovative and effective form of early language intervention with retarded language delayed toddlers.